public class StringConvert {
    public static void main (String[] args){
        int a = 10;
        double b = 12.0;
        float c = 11.0f;

        String s1 = a + "";
        String s2 = b + "";
        String s3 = c + "";
        System.out.println(s1);
        System.out.println(s2);
        System.out.println(s3);//类型转换
        System.out.println("==============");

        int a1 = Integer.parseInt(s1);
        double b2 = Double.parseDouble(s2);
        float c3 = Float.parseFloat(s3);
        System.out.println(a1);
        System.out.println(b2);
        System.out.println(c3);

        String str = "abc";
        System.out.println(str.charAt(0));
        System.out.println(str.charAt(1));
        System.out.println(str.charAt(2));
    }
}
